1. Field of the Invention
This invention relates to circuitry for distributing battery power to multiple loads such as a film drive motor and an electronic strobe flash unit in a camera. More particularly, this invention relates to circuitry which distributes power to the loads in a manner that avoids supplying battery current to the loads simultaneously.
2. Description of the Prior Art
The electrical energy a battery delivers to a load equals battery power (battery voltage times battery current) multiplied by the time during which power is delivered. The battery's energy-delivery capacity is not constant, and varies as a function of battery load. If battery voltage is halved and current is doubled, its total energy-delivery capacity can change, even though battery power is the same. An excessively loaded battery, i.e. a battery whose current is increased beyond a particular level, can suffer a significant decrease in its total energy-delivery capacity.
Energy conservation and protection of a battery from excessive current drain are particularly important when the battery provides power for multiple loads. In U.S. Pat. No. 3,846,812, a battery is protected by locking one device out when another load is actuated, rather than energizing the loads independently.
There is also known in the prior art apparatus for using energy stored in a battery circuit that would otherwise dissipate through heat or charge leakage. U.S. Pat. Nos. 3,787,704 and 3,909,747 teach that energy stored in a capacitor or a transformer's magnetic field can be returned to a rechargeable battery.